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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <h1>jsonp</h1>
    <button id="btn">发送jsonp请求</button>

    <script>
        function callback(data) {
            console.log('callback执行了,参数是:', data)


        }
        const oBtn = document.getElementById('btn')
        let oScript = null;
        oBtn.onclick = function () {
            if (oScript) {
                oScript.remove()
            }
            oScript = document.createElement('script')
            oScript.src = 'http://127.0.0.1:3000/getUser?userId=001&cb=callback';
            document.body.appendChild(oScript)
        }
    </script>
    <!-- <script src="http://127.0.0.1:3000/getUser?a=1&b=3"></script> -->
</body>

</html>